两种贯通潜孔锤反循环钻头应用效果及理论分析

Strength Analysis of New Kinds of RC Drill Bit and Its Experimental Study

对于矿区钻孔作业存在的粉尘污染严重、岩矿心采取困难等问题,常规金刚石钻进取心难以满足现场施工要求。采用贯通式潜孔锤反循环连续取心技术替代常规金刚石取心工艺,在保证了较高钻进效率的同时,可有效解决干旱缺水矿区存在的取心及其引起的污染问题,保障施工人员的身体健康。为此,笔者所在课题组研发了两种新型潜孔锤反循环钻头并进行了野外试验,同时,运用LSDYNA数值模拟对设计的两种反循环钻头进行了强度分析。试验结果表明,两种钻头均具有较好的碎岩钻进效果,但花键内喷孔式反循环钻头易发生断裂;数值模拟分析结果显示,钻头的最大应力远高于材料疲劳极限是造成钻头破坏的根本原因,数值模拟结果与试验结果取得了较好的一致性。由此证实了花键内喷孔式反循环钻头结构存在缺陷,设计时应尽量避免在内喷孔周围设置环槽,以保证钻头体强度。

For the problem of dust pollution and coring for diamond drilling in mine area,which can not meet the requirement of drilling core,in this paper,a drilling system named RC DTH hammer is used to instead of diamond drilling method.With a high drilling efficiency,the RC DTH hammer drilling method overcome the problems in mine area,especially for the pollution,core,and the health of workers.In order to make full use of the method,two new RC bits are designed and applying software LSDYNA to analysis the strength of the structures of two bits.The two drill bits made good performances in the field tests,however,the bit with nozzle holes in splines broke frequently during drilling.The simulation consequence showed that the stress of RC bit with nozzle holes in splines hasmuch larger than the allowed value of fatigue limit of 35 CrMo,which is the primary cause to this test failure.The conclusion of simulation is in great agreement with that of field test,proving that the ring slot should not be designed nearby the nozzle hoes when designing a RC drill bit.